He has insisted he is a great supporter of Sir Kim, who has dramatically quit, and has revealed that he rang him to commiserate.
It has emerged that the ambassador decided to resign after Mr Johnson – odds-on favourite to become prime minister in two weeks’ time – refused to pledge his support for him in Tuesday’s head-to-head TV debate, while his rival Jeremy Hunt backed Sir Kim to carry on.
But responding to fierce criticism, the former Foreign Secretary has told The Sun: “I can’t believe they’re trying to blame me for this.
“It seems bizarre to me. I’m a great supporter of Kim’s. I worked very well with him for years.
“I spoke to him just now to offer my good wishes. I think that he’s done a superb job.”
Asked why he failed to back him in the TV debate, Mr Johnson said: “I don’t think it’s right to drag public servants’ careers into the arena in that way.
“I thought it was most odd that the career of a particular servant should suddenly become a test case within a TV debate.”
The strongest criticism of Mr Johnson came from his former deputy at the Foreign Office, Sir Alan Duncan.
“Boris Johnson has basically thrown our top diplomat under a bus,” he said. “His disregard for Sir Kim Darroch and his refusal to back him was in my view pretty contemptible, but also not in the interests of the country.”
After Sir Kim’s resignation, over leaked memos in which he described President Trump’s administration as inept, there’s now a battle raging between allies of Theresa May and Mr Johnson over who should appoint his successor.
Downing Street has said an appointment will be made in due course.
Ministers loyal to the prime minister want her to move swiftly to appoint a replacement to deny Mr Johnson making the decision.
They claim the role is too important to be left vacant for an extended period and point out that her predecessor, David Cameron, appointed Ed Llewelyn, his chief of staff, as ambassador to France shortly after saying he was leaving Number 10.
But Mr Johnson’s supporters have warned the PM it would be unacceptable to tie the hands of her successor by appointing a new ambassador in one of her final acts in Downing Street.
Brexiteers also want a political appointee aligned with the new government’s strategy.
Mr Johnson’s role in Sir Kim’s departure has also been attacked by Labour.
Shadow foreign secretary Emily Thornberry said Mr Johnson should “hang his head in shame” over his failure to support Sir Kim.
“The fact that Sir Kim has been bullied out of his job, because of Donald Trump’s tantrums and Boris Johnson’s pathetic lickspittle response, is something that shames our country,” she said.
There is also regret in Washington over Sir Kim’s demise, even among Trump supporters.
Republican Senator Lindsey Graham told Sky News: “I’m disappointed, I thought he did a good job for our country, for both countries.
“I know him. I think what happened was deplorable. It’s going to be hard to have diplomacy work if all the stuff winds up in the newspapers and I thought he got a raw deal because in the cables he pretty much indicates President Trump is a different type of politician, calls him the Determinator and he’s likely to win.”
There are more Tory leadership hustings to come, so the row between Mr Johnson and Mr Hunt over Sir Kim’s resignation will continue.
Author: Jon Craig